Vulnerability identifier: #VU28172

Vulnerability risk: Low

CVSSv3.1: 3.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-5753

CWE-ID: CWE-200

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Signal Private Messenger for Android
Mobile applications / Apps for mobile phones
Signal Private Messenger for iOS
Mobile applications / Apps for mobile phones

Vendor: Signal Foundation

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to application discloses currently used DNS server to arbitrary user from non-contact list. The issue is related to how WebRTC processes ICE Candidates, which takes place before a user decides to answer an incoming Signal call. A remote attacker can gain access to victim's current DNS server IP address and based on this data uncover victim's geographical location.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Signal Private Messenger for Android: 4.59.0

Signal Private Messenger for iOS: 3.8.1.5

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External links
http://www.tenable.com/security/research/tra-2020-33

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.